Climb Los Pinos Mountain by mountain bike, and enjoy superb vistas of San Diego County and the borderlands.

Los Pinos Mountain's 4805-foot height hardly places it in the same league as the nearby, higher peaks of the Cuyamacas and Lagunas, but the peak does get some recognition as the site of one of the few remaining active fire lookouts in Southern California. Cleveland National Forest operates the lookout and has jurisdiction over most of the surrounding landscape.

The fire roads curving up the slopes of Los Pinos Mountain are too long and tedious for most hikers, but ideal for travel by intrepid mountain bikers. For the best views, try the following looping tour of 17 miles, up and over the top of the mountain. Truncated versions of the route are possible. Since summer's heat lingers this month, try to get an early-morning start, or wait until mid-afternoon, when evening shadows begin to drape the slopes of the mountain.

Let's assume you start at the intersection of Corral Canyon Road and Buckman Springs Road, 3.3 miles south of Interstate 8. This is within the national forest boundary, so you'll need to display a National Forest Adventure Pass on your parked car.

Begin with a warm-up on the first few, rather flat miles of Corral Canyon Road. The road leads to the Corral Canyon Off-Road Vehicle Area. If you're riding on the weekend, watch out for cars and trucks hauling ORV machines on the narrow pavement.

At a point 4.8 miles from the start, Corral Canyon Road bends sharply left and begins curving up a hillside (you'll return to this point after you come down from the mountain). Exactly at the bend, you'll see a locked gate on the right. This keeps out ORVs, but hikers and bikers can go though. Go ahead and do that.

Continue riding uphill in the shade of live oaks, now on a dirt surface. After 0.5 mile, veer left on the narrow Espinosa Trail. After another mile uphill through chaparral, you reach a saddle where Los Pinos Road intersects. Espinosa Trail continues west -- eventually into the Pine Creek Wilderness, which is off-limits to bikes. You make a left turn on the road.

Steep and rocky in places, Los Pinos Road curves up along the north flank of Los Pinos Mountain, which is dotted by willowy Coulter pines. The mammoth, fast-moving 1970 Laguna fire burned across these slopes, destroying the much thicker pine forest that used to exist here. The mountain was named after los pinos -- the pines.

Stay left where the spur road to Spur Meadow takes off. At the next intersection, higher still, another (gated) spur road slants left and continues curving up to the fire lookout tower on top, which is intermittently staffed by forest-service personnel. The vista from the top includes a wide swath of the border region, and (more commonly in winter than right now) a good stretch of the Pacific Ocean.

On beyond the summit spur, you look forward to a hefty gravitational payback -- all the way back. Zigzag down the south side of the mountain and arrive at Four Corners -- a four-way intersection in a large clearing. Take the paved road on the left (Corral Canyon Road), curl down the slope on sharp curves, return to the point where you left the pavement earlier, and continue on a gentle downhill grade back toward Buckman Springs Road.